Hi I'm kinda new. =]
I was wandering what is my level around here, what should I improve and any sorts of tips. oh yeah, it's not really my first time but it's the first i'm presenting. so...
It's pretty good actually, but you didn't pick the hardest raw page out there. Aside from a little bit of overseen dust and some white dots (which shouldn't be there) in the black, it's near perfect. I would've personally left the original borders, though.
It's pretty nice, but you're using tankoubon (volume) raw so differences are hard to notice, aside the border fix. Why not trying to clean chapter raws?
you should practice on magazine scans, you can find them on mangahelpers.com over at the r/t/s sections.